The present invention relates to an apparatus and method for use in the down-hole retrieval of pumping equipment from oil wells. Particularly, the present invention relates to an apparatus and method for cutting connecting cables which connect down-hole pumps in oil wells or other fluid producing wells, to the surface of such wells to thereby facilitate retrieval of said down-hole pump from the bore hole.
Today, particularly with respect to fluid producing wells which pump large quantities of fluid such as large quantities of salt water along with oil, it is common practice to utilize pumps positioned down-hole adjacent the bottom of the well bore or in proximity to the fluid producing strata. Such pumps are disposed down-hole at the end of a tubing string to which they are connected, in order to effect transport of the fluids passing through the pump to the ground surface from which the well bore originates.
These down-hole pumps generally require one or more cables connecting the pump to the surface of the ground. These cables supply power to the pumps and are sometimes supplied for other reasons. Most often, at least one or more of these connecting cables are required for each down-hole pump. These connecting cables extend from the down-hole pump up along the sides of the tubing string from the pump to the surface. The connecting cable is exterior of the tubing and generally is clamped to the tubing in such manner as to keep the cable in a permanent generally taut, position with respect to the tubing. The distance between the clamping devices may vary but usually the clamping devices holding the cable to the tubing will be spaced 10 to 15 feet apart.
On occasion, it becomes necessary to move the down-hole pump from the bottom of the well bore for repair or the cleaning. In many instances, due to sanding up of the lower portion of the well bore or by virtue of corrosion or other occurrence, the down-hole pump becomes rather firmly lodged down-hole and requires extreme pulling forces from the surface in order to dislodge. Also, in other instances, the down-hole pump may actually become disconnected from the tubing, thereby necessitating removal of the tubing and "fishing" for the pump which must then be brought to the surface and reconnected to the end of the tubing. In the course of pulling on the tubing to dislodge the 'stuck" down-hole pump or in pulling disconnected tubing from the well bore in preparation for "fishing" for the pump, it is relatively common that the cable referred to above which run from the pump to the surface, is accidentally broken. Very frequently, the cable is severed at a significant distance above the down-hole pump. In such instance, when the cables are severed, the lower portions of the cable fall in an irregularly coiled heap to the lower part of the well bore and onto the top of the down-hole pump. This coiled cable substantially impedes further removal of the down-hole pump, either by pulling with the tubing or in "fishing" for the down-hole pump. In fact, it usually is necessary to painstakingly remove the coiled cable, sometimes small piece by piece, in order to removal the down-hole pump or even get to it. This, of course, is relatively expensive and results in considerable down-time for the well, which in turn results in the loss of much needed production.
In addition to the cable severing and coiling down-hole on top of the pump, quite frequently, the clamping devices themselves are broken in the course of trying to pull the tubing string. The clamping devices which are usually Monel bands, also when broken, fall down upon the top of the pump. Removal of these broken clamping devices is also necessary before the pump can be removed. This removal is also slow and painstaking and thus, costly.
It is now an object of the present invention to provide an apparatus and method whereby the removal of down-hole pumps in well bores of fluid producing wells may be facilitated.
Another object of the present invention is to provide a new apparatus and method for preventing cables connecting down-hole pumps in well bores of fluid producing wells, to the surface of said fluid producing wells, and clamping devices holding said cables, from becoming coiled and piled upon the top of said down-hole pump in operations whereby it is necessary and desirable to remove said down-hole pump to the surface.
More particularly, the present invention is an apparatus and method for cutting cables attached to down-hole pumps in fluid producing wells which cables connect such pumps to the ground surface of the fluid producing well, such cutting being adjacent to the top of said down-hole pumps to thereby prevent the problem of such cables being severed at a point further distant from the top of said down-hole pump and falling in a coiled position on top of said down-hole pump, and the further problem of clamping devices holding said cables to the tubing string from becoming severed and falling on top of said down-hole pumps.
Additional objects will become apparent from the following description of the invention herein disclosed.
The present invention which fulfills the above and other objects, is, in one of its embodiments, an apparatus for severing cables connecting down-hole pumps in fluid producing wells to the surface of said fluid producing wells, said apparatus comprising (1) a cylindrical carrier member of a size to be accommodated within a tubing string in slidable and rotatable contact with the interior walls of said tubing string, (2) at least one cable grasping and severing member extending downward from a central section of the interior of said cylindrical carrier and rotatably affixed to said central section of said cylindrical carrier such as to permit rotation of said grasping and severing member through a vertical plane; (3) a vertical slotted opening in said cylindrical carrier for each of said grasping and severing members, such slotted opening being positioned such that the lower portion of said grasping and severing member may rotate in a vertical direction through said slotted opening and with the upper edge of said slotted opening being located below the rotational connection of said grasping and severing member of said cylindrical carrier to thereby limit said grasping and severing member from rotating in said vertical direction through more than 90 degrees from the vertical axis of said carrier member, (4) a tension producing means positioned within an internal portion of said carrier such as to exert force on said grasping and severing member such as to cause the lower portion thereof to rotate in a vertical direction, and (5) means for connecting said cylindrical carrier to a connecting means connecting said cylindrical carrier to the ground surface of said fluid producing well.
In another embodiment, the present invention is a method for severing connecting cables connecting down-hole pumps in fluid producing wells to the ground surface of said fluid producing wells, said severing taking place adjacent the top of said down-hole pump, said method comprising, (1) introducing a means of cutting the walls of the tubing string of said fluid producing well, into the tubing string under conditions such that the walls of said tubing string is cut adjacent the top of said down-hole pump, (2) pulling said tubing string vertically to separate the cut apart edges of said tubing a distance such as to accommodate the outward extension of the severing means of an apparatus for severing connecting cables connecting down-hole pumps in fluid producing wells to the ground surface of said fluid producing wells, but not pulling said tubing string vertically to such extent as to cause said connecting cables to sever, (3) introducing into said tubing string an apparatus for severing said connecting cables, said apparatus comprising that hereinabove described, (4) lowering said apparatus down through said tubing string until said apparatus reaches the opening between said upper and lower portions of said cut apart tubing string, whereupon said severing member is extended out through said opening to an open extension of no greater than 90 degrees from the vertical axis of said apparatus, (5) rotating said severing apparatus such that said severing member is brought into contact with a said connecting cable with sufficient force to cause said severing member to firmly engage said connecting cable, and (6) pulling said severing apparatus upward such that said cable is brought against the lower edge of said cut tubing string by said severing member with sufficient force to cause said cable to be cut.
By means of the present invention in its various embodiments, the connecting cable between down-hole pumps in fluid producing wells and the surface of said fluid producing wells is severed just above the down-hole pump, thereby alleviating the costly and time consuming problem of removing said cable when such are broken further above said down-hole pumps as above discussed and the problem of broken clamping devices piling on top of said down-hole pumps. While the description of the present invention as herein presented is directed primarily to use in oil wells, it is clearly within the scope of the present invention that it may be used with respect to any well bore holes having down-hole pumps which require cables connecting said pumps to the surface and further, require tubing strings to bring the fluid being pumped to the surface.